The long range goal of this project is to combine immunocytochemical methods with light and electron microscopy to study cellular mechanisms of myelin formation, breakdown and regeneration. Nervous tissues fom experimental animals and patients with demyelinating disease have been studied in the following current projects: 1) distribution of myelin-associated glycoprotein (MAG) and basic protein (BP) in hexachlorophene (HCP) intoxication, experimental allergic encephalomyelitis (EAE) and a genetic defect of myelin formation (jumpy mice). 2) Distribution of MAG, BP and papova virus in progressive multifocal leukoencephalopathy and use of immunocytochemical methods to identify remylination in multiple sclerosis lesions.